This present application relates generally to methods, systems, and/or apparatus for improving the efficiency and/or operation of turbine engines, which, as used herein and unless specifically stated otherwise, is meant to include all types of turbine or rotary engines, including gas turbine engines, aircraft engines, steam turbine engines, and others. More specifically, but not by way of limitation, the present application relates to methods, systems, and/or apparatus pertaining to improved turbine blade diagnostics, including the usage of RFID technology to transmit status information that may be used in diagnostic applications.
A gas turbine engine typically includes a compressor, a combustor, and a turbine. The compressor and turbine generally include rows of blades that are axially stacked in stages. Each stage includes a row of circumferentially-spaced stator blades, which are fixed, and a row of rotor blades, which rotate about a central axis or shaft. In operation, generally, the compressor rotor blades rotate about the shaft, and, acting in concert with the stator blades, compress a flow of air. The supply of compressed air then is used in the combustor to combust a supply of fuel. Then, the resulting flow of hot expanding gases from the combustion, i.e., the working fluid, is expanded through the turbine section of the engine. The flow of working fluid through the turbine induces the rotor blades to rotate. The rotor blades are connected to a central shaft such that the rotation of the rotor blades rotates the shaft.
In this manner, the energy contained in the fuel is converted into the mechanical energy of the rotating shaft, which, for example, may be used to rotate the rotor blades of the compressor, such that the supply of compressed air needed for combustion is produced, and the coils of a generator, such that electrical power is generated. During operation, because of the extreme temperatures of the hot-gas path, the velocity of the working fluid, and the rotational velocity of the engine, turbine blades, which, as described, generally include both the rotating rotor blades and the fixed, circumferentially-spaced stator blades, become highly stressed with extreme mechanical and thermal loads.
Given these conditions, it is important for compressor and turbine rotor blade health to be monitored closely. As one of ordinary skill in the art will appreciate, a blade failure may cause catastrophic and expensive damage to a turbine engine. Generally, many such blade failures may be predicted and, thereby, avoided if data concerning strain levels and/or crack formation/propagation in certain highly stressed areas on the blade is accurately collected and monitored. Generally, though, such data is either impossible or prohibitively expensive to collect and, when it is collected by conventional means, the data is unreliable. For example, tip timing is a conventional method that measures blade vibration frequency. It is believed that the presence of a crack alters the operating vibration frequency of a blade and, thus, may be used to warn of a compromised blade. However, results from this method have proved unreliable in many applications. Of course, another method is to shut down the turbine engine and the visually inspect the blades. This type of inspection, though, provides no information about the stress occurring during operation, is also prone to unreliability, and is very expensive because of both the required labor and the need to shut down the engine. As a result, there is a continuing need for methods, systems, and/or apparatus pertaining to improved turbine blade monitoring and diagnostics and, particularly, accurate ways of monitoring and accessing rotor blade health while the turbine is operating.